Telephone-receiver



Ulllllllllmllm (No Model.)

J. T. GUTHRIE.

TELEPHONE RECEIVER.

No. 341.000. Patented May 4, 1886.

UNITED STATES PATENT OEEIcE.

JAMES T. GUTHRIE, OF LEESBURG, OHIO.

TELEPHONE-RECEIVER.

aPEcIPiCa-TION forming part of Letters Patent No. 341,000, dated May 4.1886.

Application filed November 10, 1885. Serial No. 182,326. (No model.)

'make and use the same.

My invention relates to an improved telephonie receiving apparatusdesigned especially for use with direct electric currents, or such asare not intermittently reversed. It is,however, capable of beingoperated by reversed currents, or such as emanate from the secondarycoil of an inductorium.

The objects of my improvement are to enable articulate speech to becommunicated by means of electricity over greater distances thanheretofore deemed practicable, and to render the spoken messagesloud anddistinct when received.

lVith these ends in view my invention consists'in a receiving-telephonecomposed of a suitable trumpet-like case, a metallic diaphragm mountedacross the enlarged end of said case, and a permanent magnet arrangedwithin said case to attract the diaphragm, and having a coil ofinsulated wire mounted on each end, said coils being connected inmultiple are to two common terminals arranged for circuit-connection.

The construction and operation of my new receiving-telephone will bereadily understood from the following particular description inconnection with the accompanying drawings.

In the drawings, Figure l is a front view of a telephonesubse1ibei"s-station apparatus comprising my improvedreceiving-telephone and its adjunets. Fig. 2 is a diametric sectionthrough the case and diaphragm of the receiver, but showing the interiorparts in full lines. Fig. 3 is a diagram illustrating theelectro-magnetic construction of the receiver.

Referring to Fig. I, at the top of the back board, A, is mounted anelectric bell, B,whieh is of ordinary construction and need not be hereparticularly described. T is the transmitter,C the battery-case, and Ethe circuitbreaking device for calling purposes. R designates thereceiver.

Referring now particularly to Fig. 2, I will first describe theconstruction of receiver R in detail, and explain the same withreference to Fig. 3. larged at both ends, and at one end is providedwith an ear-piece, I?,whiel1 hasa fiange orlip, p, embracing the end ofthe case snugly, and preferably lined with velvet or similar cloth togive it adherence. At s the ear-piece has an annular shoulder, andbetween this shoulder and the adjacent end of the case is clamped thediaphragm D. Inside of the case is a bar permanent magnet, M, having onepole near the diaphragm and the other pole near the other end of thecase. On the diaphragm end of the magnet is a coil, K, of ine insulatedwire, and a similar coil, K', is on the other end. 'Ihe inner terminalof coil K isrconnected to the outer terminal of coil K, and the innerterminal of the latter is connected to the outer terminal of the former.The double terminals thus formed are connected to the binding-postsp andp,respeetively,so that the two coils will thus be in multiple-areconnection with wires which may be connected to posts p p. A currentpassing in the direction of the arrows No. l, through the wires L and Lto and from the receiver,will divide at the junction y ofthecoil-terminals and reunite at the junction i', a quantity going througheach coil in proportion to its resistance. The resstances should beequal. The coils are so wound and arranged upon the magnet that when thelcurrent through one coil tends to reenforce the magnet-pole which itsurrounds the current through the other coil partially neutralizes theother pole. Now, ifa current is used which ilows only in one direction,and is simplyincreased and decreased in strength or varied in responseto sound undulations, the current action which strengthens themagnet-pole nearest the diaphragm weakens the other polc,and themagnetic field is shortened and condensed near the diaphragm, and theattraetionof the magnet for the diaphragm is much greater than it wouldbe if its iield were not so condensed. At the same instant the field isweakened atthe opposite pole, there being no necessity for strongattraction or any other magnetic action at such time at that Thetrumpet-like case r is en' IOO point. however, the rear pole begins togain strength as the front pole loses it, and the magnetic ield near thediaphragm becomes weakened by attenuation, resulting from extension andfrom the loss oi' the exciting induencc of coil K, so that the diaphragmis so much relieved as to make a very free outward half-vibration as theresult of its natural resilience. The coniplete vibrations correspond tovariations of current strength, and by means of my improved transmitter,described and claimed in another application, the impulses varied instrength are all caused to flow in the same direction. XVhen the twocoils act upon the magnet in opposite directions,there is occasioned atorsional strain which tends to induce in both coils additional currentswhich react upon the magnet, and thus rcenforee the impulses which comefrom the transmitter.

On the rear end of the trumpetlike casing` is a metal plate, I, throughwhich passes an adjusting-screw, i', which screws into the .rear end ofthe bar-magnet, and serves to adjust the same withrelation to thediaphragm. The screw has a collar, z", which prevents it from movinglongitudinally through the plate.

Vhile I have described my receiver as bcing especially adapted foroperation by nonalternating currents or undulations, it may be alsooperated by the alternating or reversed currents such as are sent bytransmitters using induction-coils.

Vhen the current begins to weaken,

I do not confine myself to the arrangement of coils as heretoforedescribed, and as shown in my drawings, as they may be so arranged thatthey will simultaneously strengthen and simultaneously weaken the1nagnet-p0les which they surround, respectively.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is

l. In areceiving-telephonc, the longitudinally-adjustable straightbar1nagnet having 4coils arranged upon its opposite ends, and connectedin multiple are, and arranged to have opposite effects simultaneously,essentially as set forth.

2. The receiving-telephone composed of the trumpet-like casing, thediaphragm, the straight bar-magnet longitudinally adjustable within saidcasing, and the coils on opposite ends of said magnet and connected inmultiple are, said coils being arranged to have opposite effectssimultaneously, essentially as sct forth.

In testimony whereof I have signed this specification in the presence oftwo subscrib ing witnesses.

JAMES T. GUTHRIE.

Ti t n ess es W. T. HovAN, L. L. SEcRrsr.

